This proposal requests partial funding for the workshop "Biocomplexity VI: Complex Behavior in Unicellular Organisms," jointly organized by the Biocomplexity Institute at Indiana University and the Biocomplexity Center at the University of Notre Dame. The workshop aims to be broader in scope and more interdisciplinary than other workshops, while remaining focused on a clearly defined problem. It will bring together researchers in many disciplines (including experimental and theoretical biology, biophysics, engineering, mathematics and computer science) to discuss current and future problems in collective phenomena in single-celled organisms, including comparison between prokaryotic and eukaryotic behaviors, motility and taxis, multicellular aggregation and biofilms, distributed behavior and intercellular signaling, differentiation and development and pathenogenic and symbiotic interactions. The talks will cover length scales from single molecule interactions and genetics to systems biology and ecology. A specific goal of the workshop is to bring experimentalists and modelers and engineers and basic researchers together and to include people who would not normally attend the same conference. This cross fertilization should improve our understanding of the fundamental biology of collective behaviors, lead to more useful models and engineering techniques, initiate new modeling efforts, promote collaborations between experimentalists and modelers, transfer best practice between subdisciplines and encourage more holistic approaches to problem solving. We have already more than forty confirmed speakers from the USA, Canada, Europe, Israel and Japan and anticipate a total participation of about 100 including a substantial number of postdoctoral fellows and graduate students. The workshop will include a significant educational component directed at graduate students and junior scientists, especially those not currently involved in complex phenomena in single celled organisms, but interested in learning about open problems, methodologies and opportunities. As part of our outreach effort we will sponsor a large public lecture for nonscientists and interested members of the community at large to be given by Dr. Eshel Ben-Jacob of the Weizmann Institute, Israel.